通过camera控制闪光灯

	if(camera == null){
	camera = Camera.open();

	public static void turnOn(Camera mCamera) {
		Parameters mParameters = mCamera.getParameters(); 
		mParameters.setFlashMode(Parameters.FLASH_MODE_TORCH);
		mCamera.setParameters(mParameters); 
		mCamera.startPreview();
	}
	public static void turnOff(Camera mCamera) {
	    Parameters mParameters = mCamera.getParameters(); 
	   mParameters.setFlashMode(Parameters.FLASH_MODE_OFF);
	   mCamera.setParameters(mParameters);
	}
	camera.release();